According to this TEDX talk, it might take as little as 3.5 percent of a country’s population to engage in successful civil resistance against a brutal dictator. In case you’re wondering: The population of the U.S. is 319 million, and 3.5 percent of that would be 11.1 million.

The straightforwardly-titled What Calling Congress Achieves, from The New Yorker, is a heartening and nuanced look at the history of constituents calling their Congressfolk and bringing us up to the present crush of activity, and how effective it has been. (Spoiler alert: Very!)